1. Field of the Invention
This invention relates generally to a method and apparatus for extracting information from the gray scale image containing "back scatter" energy generated by a focused beam of energy (ultrasound, radar, sonar) striking an echoic surface target. Ultrasound imaging of a target such as human tissue is utilized to recognize and identify the resultant echoic characteristics of the target. Specifically the invention relates to a method and apparatus for inexpensively extracting significant image information based on edges, lines, contours and geometrical shapes from an image containing back scatter image patterns in real time.
2. Description of the Prior Art
The use of ultrasonic energy producing echoic information concerning the health and well being of body organs and tissues is well known. Gray scale echography which provides characteristics of tissue texture in a visual image display representative of tissue and cell differences due to disease or lesions is also known. A beam of focused ultrasonic energy on a tissue target produces parameters with respect to the tissue including attenuation and back scattering. A complete discussion of texture and tissue echograms can be found in the Journal of Ultrasound Medicine Volume 9, pages 215-229, 1990.
The present invention deals with echoic back-scatter information as well as geometric line and shape information which are contained in a processed image in a visual x and y coordinate system on a cathode ray tube as a function of visually reproduced pixels. In particular, computerized image processing and visual image processing including pattern extraction and recognition is known. U.S. Pat. No. 4,769,850 issued to Itoh et al Sep. 6, 1988 shows an apparatus for extracting circular and linear components in a complex computerized image. Likewise U.S. Pat. No. 4,866,783 issued to Ohyama Sep. 12, 1989 shows a system for detecting edges of an image which includes a scanning circuit and other components for evaluating the image. U.S. Pat. No. 4,817,171 issued to Stentiford Mar. 28, 1989 shows a pattern recognition system for syntactic decision processing.
U.S. Pat. No. 4,908,872 issued to Toriu et al Mar. 13, 1990 shows a method and apparatus for extracting contour lines from a pattern obtained in image processing using vector gradients for comparing gray level gradients among adjacent pixels. To date, the primary problem with the prior art systems are the mathematical complexity and the time and computing power required for extracting relevant image information cost effectively in real time. Using current image processing methods, geometric pattern extraction and recognition is extremely complex and a multi-step mathematical process which requires the power of a super computer to process images in real time.
With respect to the ultrasonic imaging of target tissue, the interaction between the "back scatter" and the primary returning energy causes variations in the intensity of the primary returning energy which shows up in the resultant image as a textured surface with gray scale brightness differences represented by the pixel array relating to the relative intensity of the returning energy from the target at specific x and y positions. The present invention, for example, can be used for example to analyze an image produced by the ultrasonic scanning of a thin, planar area of tissue located within the focal length of the ultrasonic emitter. The invention analyzes the multidimensional patterns contained in the back scatter and the geometrical lines and shapes, i.e. geometrical patterns; all of which are contained in the image produced by the scanning energy beam. Topographical variations appear as the gray scale pixel luminence intensity variations distributed across the image area presented.
The present invention discloses a method and apparatus using personal sized computers such as an IBM PC, to provide real time image analysis and evaluation to discern relevant information patterns in the back scatter component of the image for differentiating cells and tissues which heretofore were not discernible without a super computer or invasive surgery accomplished at a resolution level to ensure the reliability of the procedure.
The present invention provides a less complex technique for complex image processing by a novel examination of predetermined target pixel radials extending from the target pixel for analysis of surrounding pixel gray scale value variations between the target pixel and neighboring near and far pixels surrounding the target pixel.